Prayers headed your way. I am about to look up palsy gait and the tiptoeing. Do not panic. Is there a way that she can articulate if she is in terrible, not so terrible, sort of pain? What is the worse that you are thinking? Autism or not she is still in possession of a lot of other faculties and she might simply be kind of harboring some nervousness or other things. Grinding of teeth occurs in all humans at times so she might actually have done it sometimes whether you were aware of it or not. I know when my children were sick all I did was watch them and saw them do all sorts of things...Take her to the doctor and please let us know how it turns out. In the meantime I hope my prayers help.